Hypertension

Question 1

Causes of Secondary Hypertension...
Combined with hypertension, what conditions do these features suggest?
1. Muscle cramps, weakness
2. Palpitations, sweating
3. Palpitations, sweating, anxiety, tremor
4. History of prematurity/NICU admission
5. History of radiotherapy
6. Brittle asthma
7. Headache and vomiting

Answer 1

1. Primary aldosteronism (hypokalaemia)
2. Phaechromocytoma, neuroblastoma, caffeine
3. Hyperthyroidism
4. Renal artery stenosis/abdominal aortic stenosis
5. Same
6. Steroid use
7. Raised ICP, SOL

Question 2

What percentage of hypertension in paediatrics is essential hypertension?

What is the most common cause of secondary hypertension?

What percentage of secondary HTN does this represent?

Answer 2

60%

Renovascular or renal parenchymal disease

90%

Question 3

What are the initial investigations for a well patient with newly diagnosed hypertension?

Answer 3

Urine: dipstick, MC&S, protein:creatinine ratio
Bloods: Renal function, electrolytes, calcium, TFTs, uric acid, metabolic (glucose, lipids, LFTs if essential)
ECG
CXR
Renal USS

Question 4

What might the next phase of investigations include?

Answer 4

Echo
Renal Doppler
Serum renin/aldosterone
24 hour urinary cortisol
24 hour urinary catecholamines
CT or MR Angiography
Renal nuclear medicine scan

Question 5

What are the indications for pharmacological treatment of essential hypertension in children?

Answer 5

Persistent hypertension despite lifestyle modifications
Symptomatic hypertension
End organ damage eg LV dysfunction, proteinuria
Diabetes
Dyslipidaemia
Family history of early HTN complications

Question 6

What are the first line antihypertensives?

Who would you avoid ACE inhibitors in?
Who are they particularly beneficial for?

Which group are best for those with asthma?

Answer 6

Usually ACE inhibitors or calcium channel blockers

Avoid: Risk of pregnancy, asthma
Benefit: Diabetes, renal failure, obesity
Asthma: Calcium channel blockers

Question 7

What is hypertensive urgency?

What is a hypertensive emergency?

How do you treat a hypertensive crisis?

Answer 7

Urgency: BP >99th centile x3 readings, 30 minutes apart
Patient is symptomatic (eg headache, nausea) but there is no evidence of end organ damage

Emergency: Severe elevation of blood pressure associated with a clinical picture of rapid and progressive end organ deterioration eg left ventricular failure, encephalopathy, renal failure, retinopathy

Question 8

How do you manage a hypertensive emergency?

How quickly should the BP drop?
What do you give if you drop the BP too quickly?

What BP are we aiming for?

Answer 8

ABC
Urgent treatment to lower BP (but slowly)
Drugs to be given in ICU, need invasive BP monitoring
D/w Paediatric Renal SMO
Secure IV access before commencing therapy
Monitor BP and pupillary responses frequently during therapy
Medical options include: IV Labetalol, Sodium nitroprusside, IV Hydralazine.

Aim to reduce blood pressure by one third of the total planned reduction in the first 24 hours, and the remaining 2/3 over the next 48 to 72 hours.
Give normal saline boluses if it falls too quickly.

Goal is to reduce to around 95th centile

Question 9

What happens to the RAA system in renovascular hypertension?

Which is the most effective anti-hypertensive for renovascular HTN?

What is the risk with this medication?

Answer 9

Reduced renal blood flow is detected&raquo_space; increase in Renin
Activation of whole system means systemic hypertension is maintained, as pressure in renal afferent arterioles will continue to be low

ACEi are most effective but can cause drop in GFR